The development of metal halide perovskite/perovskite heterostructures is hindered by rapid interfacial halide diffusion leading to mixed alloys rather than sharp interfaces. To circumvent this outcome, we developed an ion-blocking layer consisting of single-layer graphene (SLG) deposited between the metal halide perovskite layers and demonstrated that it effectively blocks anion diffusion in a CsPbBr3/SLG/CsPbI3 heterostructure. Spatially resolved elemental analysis and spectroscopic measurements demonstrate the halides do not diffuse across the interface, whereas control samples without the SLG show rapid homogenization of the halides and loss of the sharp interface. Ultraviolet photoelectron spectroscopy, DFT calculations, and transient absorbance spectroscopy indicate the SLG has little electronic impact on the individual semiconductors. In the CsPbBr3/SLG/CsPbI3, we find a type I band alignment that supports transfer of photogenerated carriers across the heterointerface. Light-emitting diodes (LEDs) show electroluminescence from both the CsPbBr3 and CsPbI3 layers with no evidence of ion diffusion during operation. Our approach provides opportunities to design novel all-perovskite heterostructures to facilitate the control of charge and light in optoelectronic applications.
|Number of pages
|Journal of the American Chemical Society
|Published - Feb 1 2023
Bibliographical noteFunding Information:
This work was supported by the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier Research Center funded by the Office of Basic Energy Sciences, Office of Science within the U.S. Department of Energy through contract number DE-AC36-08G028308. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. T.L. and K.R.G. ackknowledge support from the National Science Foundation (award number OIA-1929131) for ultraviolet phoelectron spectroscopy measurements. D.D. carried out DFT simulations as part of a Research Experience for Undergraduate students program supported by the National Science Foundation (award numbers 2050900, 2050841, and 2050764 and ECCS-2025064). Any opinions, findings, and conclusions or recommendations expressed in this material do not necessarily reflect the views of the National Science Foundation. This research used resources of the National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy (DOE) Office of Science User Facility operated under Contract no. DEAC02-05CH11231.
© 2023 The Authors. Published by American Chemical Society.
ASJC Scopus subject areas
- Chemistry (all)
- Colloid and Surface Chemistry